Fixing glues (also known as adhesives or else mastics) are widely used by individuals in their indoor works in order to fasten the most diverse articles to the floors, walls or ceilings and thus avoid the use of conventional mechanical fixing systems based, for example, on nails, screws and/or rawlplugs. The fixing mastics widely available nowadays thus make it possible to fasten, for example to a vertical surface, articles of very large weight that correspond to the application to the bonding joint (or adhesive joint) of shear stresses of around 15 kg/cm2 to 100 kg/cm2. The nature of the substrate to which the article may be fastened is itself very varied; mention may especially be made of plaster or ceramic tiles, concrete, asbestos cement, or else wood.
It is thus possible to envisage the fastening, by bonding, of articles such as, for example, spotlights for lighting, hooks, mirrors, pegs or coat racks of various shapes, curtain rod supports and even supports for shelves intended for storing crockery, kitchen utensils or books.
The solidity of the assembly thus produced results from the excellent cohesion of the adhesive joint of around 0.1 to 2 millimeters in thickness by which the article is fastened to the substrate. The solidity of the assembly is also the result of the quality of the adhesion between the two faces of said joint and, respectively, the article and the substrate.
The solidity of the assembly obtained by the fastening of these articles to the various substrates however raises the question of their separation with the consumer, especially when the latter desires to refit his home, or else in the case of a change of occupant of the dwelling premises. There is thus a serious risk either that the individual would not be able to detach the article fastened to the substrate, or that the separation achieved by force results in the article and/or the substrate in question being damaged.
Patent application US 2006/0178470 describes a composition suitable for use as a fixing adhesive, which comprises less than 15% by weight of a polyurethane containing a silyl group and from 20 to 95% by weight of a filler. This adhesive offers a good separability between the bonded article and the substrate, also referred to as reversible adhesive behaviour; this separation takes place by a cut made in the bulk of the adhesive joint using a suitable cutting tool such as a spatula, a scraper or else a metal wire. This separation is however accompanied by the presence of residues originating from the adhesive joint which are solidly fastened both to the separated article and to the substrate, the removal of which requires difficult work of scraping with a spatula and which may prove practically impossible in the case of rough substrates such as wood, concrete or asbestos cement.